Liquid dispensing systems capable of drawing patterned microlines for use in applications, such as in organic electronics, use various approaches. Such approaches include microcontact printing, screen-printing, photolithographic printing, and inkjet printing. These systems place small amounts of liquid containing semiconducting polymer molecules or conducting ink particles onto a substrate to form circuitry. It is important that the dispensed liquid be of a generally sufficient quantity for proper subsequent process. None of the prior approaches, however, includes an intrinsic mechanism to sense the properties of the dispensed liquid. While exterior vision systems have been employed to sense the liquid dispensing process, it would be difficult to detect defective spots in a practical and accurate manner using these systems. In addition, these exterior vision systems increase the cost of the overall system.
In addition, none of these approaches lends themselves to the detection, in real-time, of defective deposition patterns. Thus, it would be desirable to develop an improved non-contact liquid dispensing system which allows for the detection of defects in-situ and in real-time.